In the case of fixation of fractures of the femoral neck, it is known to employ a tool that includes a guide pin positioned inside of a sleeve. U.S. Pat. No. 4,450,835, issued for an invention of Asnis et al. The two components are configured to function in cooperation with one another at one end like a drill bit, so that the tool can be inserted in bone, and the sleeve then withdrawn, leaving the guide pin in place. Col. 2, line 57, to col. 3, line 68; col. 5, line 36 to col. 8, line 35. The guide pin can then serve to position cannulated screws in the bone. The guide pin is apparently retained in the sleeve solely by action of a Trinkle fitting in a surgical drill, col. 5, lines 55-56, and col. 6, lines 51-58, yet its surrounding sleeve apparently can be dislodged after removal of the tool from the fitting only by tapping the guide pin forward in the sleeve with a mallet, col. 7, lines 53-56, a procedure that may encounter some difficulty depending on the relative position in bone of the drilling ends of the sleeve and the guide pin. The tool is said, without explanation, to be applicable to any surgical procedure involving insertion of a guide pin for a cannulated surgical implant. Col. 3, lines 62-65.
The repair of a ligament tear (for example, a collateral ligament tear) frequently involves the need to affix a ligament to bone. Currently both staples (which may be metal or of an absorbable material such as polylactic acid) and washered screws are used for this purpose. Staples, while apparently convenient, may not provide as secure an affixation as screws, while screws are difficult to use. The convenience of staples may in fact be somewhat illusory, since it is recommended, for example, in the case of many staples to drill pilot holes for each staple leg.
The affixation by washered screws requires predrilling through both the ligament and the bone, a procedure requiring typically that the ligament be held in place during the entire drilling period, and thereafter while removing the drill and inserting the screw. However, it is difficult to hold the ligament in place during the entire time required by such a procedure. Moreover, because ligaments have directional fiber bundles, these bundles tend to separate to a certain degree dependent upon any force exerted on the bundle in the axial direction (that is in the direction of the pilot hole for the screw). When the pilot hole drill is removed, the fiber bundles tend to close back together again, making the visual location of the pilot hole center difficult at best.
One approach to dealing with the problem involves seeking to insert a guide pin quickly into the pilot hole immediately after the drill bit is removed; the screw is then inserted either over the guide pin (in case the screw is cannulated) or beside the guide pin (in case the screw is not cannulated). However, this approach is not always successful, nor is it easy.
Washers have been employed to prevent the ligament from wrapping around the head of the screw as it approaches maximum torque application and to assist in distribution of the forces from the screw head more evenly across the ligament. However these washers are prone to rotation and the ligament moves underneath the washer.